OBESITY ANESTHESIA Flashcards Preview

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Flashcards in OBESITY ANESTHESIA Deck (196)
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1
Q

When performing a spinal anesthetic on a morbidly obese individual, you know that you should

A

use a lower volume of local anesthetic

2
Q

What is the most reliable test for detecting an inadvertent intrathecal or intravascular epidural catheter placement in a laboring parturient?

A

Negative aspiration for CSF or blood

3
Q

**What is the only ventilator adjustment shown to improve respiratory function consistently in obese individuals? WAS on SEE EXAM

A

PEEP

4
Q

If a drug distributes primarily to lean tissues, then its loading dose should be based upon the patient’s

A

Lean body weight

5
Q

The recommended tidal volume for an obese patient should be estimated as

A

Predicted body weight

6
Q

Tubular renal tubular reabsorption and GFR in obesity

A

Increased

7
Q

Sodium excretion with obesity is

A

Decreased/ impaired

8
Q

Increase in direct proportion to body weight

A

Plasma cholinesterase activity

9
Q

FRC and obesity

A

Decreases exponentially as BMI increases

10
Q

2 warning sings of diminished cardiovascular reserve amd CV complications in OBESES PATIENTS.

A

ORTHOPNEA

Paroxysmal nocturnal apnea.

11
Q

2 preop interventions for Obesity : HOB and consideration for OSA

A

Head up 30 degrees

CPAP prior to induction if OSA

12
Q

Airway that is very helpful to achieve if difficult ventilation of the obese

A

LMA

13
Q

3 Most important intraoperative consideration for obesity: comment on TV, PEEP and fiO2. Why do you want FiO2 that you mentioned?

A

TV 6-8 ml/kg of IBW (to avoid overdistention)
PEEP 10-12 cm H2O
FIO2 less than 0.8 because INCREASED FIO2, accelerates atelectasis.

14
Q

3 Most important POST-operative consideration for obesity:

A

CPAP or BIPAP
O2
Head up

15
Q

Intestinal mobility and regioonal

A

Early recovery of intestinal mobility

16
Q

This medication is not suitable for bariatric surgery and why?

A

ketorolac; increased chance of GI bleed.

17
Q

The most severe post op complications for bariatric surgery

A

Anastomotic leaks and strictures
PE
Sepsis
Gastric prolapse and bleeding

18
Q

Most common signs and symptoms of anastomotic leaks from most common to least

A

Tachycardia
Fever
Abdominal pain

19
Q

What is the most sensitive sign of an anastomotic leak?

A

Tachycardia (HR >120)

20
Q

Mortality of Roux en Y bypass

A

0.5-1%

21
Q

Most serious metabolic complication of bariatric surgery

A

Severe malnutrition ; red meat poorly tolerated

22
Q

Associated with biliopancreatic conversion?

A

Fat soluble vitamin malabsorption

23
Q

FAT soluble vitamins are

A

ADEK

24
Q

Ideal gas for obese patients

A

Low solubility

25
Q

You can use all 3 MRs for obese patients but which one is preferred and why?

A

Vec, roc, cis

cis preferred because organ-independent mechanism (HOFFMAN)

26
Q

When blood loss is replaced , the ____ratio

A

3:1

3 mL of cristalloid for 1 ml blood loss.

27
Q

Any advantage of Large TV for obese patients?

A

NO

28
Q

Anatomical issues with the obese patients when in comes to regional anesthesia

A

Obscured bony landmarks

29
Q

LA requirements in ______in the obese patients? why?

A

Decrease; because of the fatty infiltration and vascular engorgement caused by intra-abdominal pressure, which decreases the volume of the epidural space.

30
Q

Extubation criteria for obese patients as far as RR and SPO2

A

RR >10 and < 30

SPO2 > 95% on < 0.4 FiO2

31
Q

Extubation criteria for obese patients as far as TV and VC

A

TV 5ml/kg IBW

VC 10-15 ml/kg IBW

32
Q

Supine position for obese: parameters affected

A

FRC and oxygenation are decreased

33
Q

Position preferred and why?

A

Lateral decubitus positiion; better diaphragmatic excursion

34
Q

What provides the safest safe apnea period during induction of anesthesia?

A

HEAD up position (Reverse trendelenburg)

35
Q

CUFF with a bladder that encircles

A

75% of the UPPER ARM CIRCUMFERENCE

36
Q

How is preoxygenation during induction in obese different from regular patients?

A

4 vital capacity breaths with 100% oxygen for 30 seconds, are superior to the 3 minutes of 100% preoxygenation.

37
Q

The object of patient position for the intubation is to position the

A

chin at HIGHEST LEVEL than the chest.

38
Q

Stacking for intubation is to

A

placing towels or folded blankets under the shoulder and head to compensate for the exaggerated flexed position of posterior cervical fat.

39
Q

BEYOND STACKING step is the

A

HELP (Head elevated Laryngoscopy position)

40
Q

HELP significantly

A

Elevates the patient’s head, upper body and shoulder above the chest.

41
Q

What is the most common mononeuropathy after bariatric surgery?

A

CARPAL TUNNEL SYNDROME

42
Q

Regular OR tables have a MAX weight limit of approximately

A

200 kg

43
Q

A difficult airway relation to BMI

A

NOT CLOSELY correlated with BMI/

44
Q

What is the single major predictor of problematic intubation in morbidly obese patients?

A

Patient’s neck circumference.

45
Q

What is a normal neck circumference for a 70 kg male?

A

about 35 cm

46
Q

Probability of difficult intubation for a male with a neck circumference of 40cm

A

5%

47
Q

Probability of difficult intubation for a male with a neck circumference of 60cm

A

35%

48
Q

my mnemonic AMTOMA difficult intubation

A
Age (increase age)
Male
TMJ pathology
OSA
Mallampati III or IV
Abnormal upper teeth
49
Q

Anatomic changes associated with obesity that contribute to difficult airway: JOINTs

A

Limited movement Atlanto-axial joint and CERVICAL SPINE by upper and lower cervical fat pads

50
Q

Anatomic changes associated with obesity that contribute to difficult airway: Mouth and pharynx changes

A

EXCESSIVE Tissue folds in mouth and pharynx

51
Q

Anatomic changes associated with obesity that contribute to difficult airway: NeCk changes

A

Short THICK neck

VERY thick submental fat (double chin)

52
Q

Anatomic changes associated with obesity that contribute to difficult airway: Cervical

A

Suprasternal, presternal, posterior cervical fat.

53
Q

Obesity and medication on DOS, except

A

Continue all except oral and oral hypoglycemics.

54
Q

Medications. that must be discontinued?

A

Anorexiant drugs and herbal supplements for 14 days

55
Q

Increased risk of infection in the obese necessitates

A

ABT prophylaxis

56
Q

Medication to be considered for anxiolysis for the obese patients? why?

A

Dexmedetomidine ; low resp depressant effects

57
Q

Effective at reversing low BP in the obese

A

Phenylephrine.

58
Q

3 main system to assess during the preop of an obese patients/

A

CV
RESP
Hepatic function

59
Q

ECG evidence of RV failure; 2

A

Right axis deviation

TALL PRECORDIAL R WAVES

60
Q

What is the most useful confirmation of pulmonary HTN?

A

TRICUSPID REGURGITATION on ECHO

61
Q

Increase probability of OS is

A

NECK CIRCUMFERENCE > 40 cm

62
Q

Common deficiencies in obese patients

A
CaFIB
Calcium
Folate
Iron
B12
63
Q

What can lead to ACUTE POST-GASTRIC REDUCTION SURGERY NEUROPATHY?

A

Vitamin and nutritional deficiencies

64
Q

Initial doses for obese patients are based on ____

A

LBW (Lean body weight)

65
Q

Why are initial doses for obese patients based on Lean body weight (LBW) ?

A

Because LBW is HIGHLY CORRELATED with CO and drug clearance

66
Q

Subsequent doses for obese patients based on

A

responses to initial dosing

67
Q

Propofol dosing : Loading , Maintenance

A

Loading: TBW ; Maintenance: LBW

68
Q

Midazolam dosing is based on

A

TBW

69
Q

Thiopental dosing is based on

A

LBW

70
Q

CIS- ATRACURIUM and ATRACURIUM dosing : Loading , Maintenance

A

Loading: TBW ; Maintenance: LBW

71
Q

3 drugs with different dosing TBW then LBW

A

Propofol
Atracurium
Cis-atracurium

72
Q

Succinylcholine dosing is based on

A

TBW

73
Q

Fentanyl remifentanil, sufentanil dosing is based on

A

LBW

74
Q

ROC and VEC dosing is based on

A

LBW

75
Q

Pancuronium dosing is basd on

A

TBW

76
Q

TBW dosing summary :

A

T- MI-SU-CI- A- PANDENE

77
Q

What are the 2 pharmacokinetics principles to keep in mind when determining drug dosing for OBESE patients?

A

Vd and Clearance

78
Q

What is the key to the administration of the loading dose:

A

Volume of distribution

79
Q

A drugs that is WATER soluble should be based on

A

LEAN body weight (WATLe)

80
Q

A drugs that is LIPID soluble should be based on

A

TBW (LiT)

81
Q

How do you calculate Lean BODY weight?

A

IBW + (20-40%)

82
Q

How do you calculate IBW?

A

Height in cm - 100 Male

Height in cm -105 female.

83
Q

What is crucial to the maintenance dose?

A

CLEARANCE

84
Q

To remember: MAINTAIN CLEARANCE in CRNA school

A

maintenance - clearance.

85
Q

Volume of the central compartment in the obese patients is

A

unchanged.

86
Q

Absolute body water content for obesity?

A

DECREASED

87
Q

Lean body and adipose tissue mass are _______ in the obesity which affect _____and_______

A

INCREASED; Lipophillic and polar drug

88
Q

Show significant increases in VD

A

Highly Lipophillic drugs such as benzodiazepines.

89
Q

Lipophillic and half life

A

Greater distribution to fat store leads to longer elimination of half life.

90
Q

TBW in obese patients

A

Decreased

91
Q

Total body fat in obese

A

INCREASE

92
Q

Lean body mass in obese

A

Increase

93
Q

Protein binding in obese

A

ALTERED protein binding

94
Q

BV in obese

A

Increase

95
Q

CO in obese

A

Increase

96
Q

Serum free fatty acids in obese

A

INCREASE

97
Q

Exception to these concepts are the highly lipophillic drugs are

A

digoxin
Procainamide
Remifentanil

98
Q

This decreases the plasma concentration of rapidly injected IV drugs

A

Increased Blood volume, dilution

99
Q

FAT has ____Blood flow and drugs dose based on _______ could lead to

A

Low: Excessive plasma concentrations use LBW insdead.

100
Q

Blood triglycerides and obesity? Effect on drug

A

Increased; reduces free drug concentration

101
Q

Serum cholesterol and obesity

A

Increased

102
Q

Alpha-1 Glycoprotein and obesity

A

INcreased blood alpha 1 glycoprotein which lead to reduced free drug concentration

103
Q

Frequent in patients having laparoscopic bariatric surgeries

A

RHABDOMYOLYSIS (1.4%)

104
Q

What should alert the anesthetist of Rhabdomyolysis after surgery of bariatric patients?

A

Unexplained elevation in Creatinine and CK levels

Complaints of buttocks, hips, and shoulder pain.

105
Q

RHABDO: Stimulate diuresis with this medication

A

mannitol

106
Q

May be necessary when rhabdomyolysis

A

Hemofiltration may be necessary for rapid clearance of myoglobin

107
Q

URine in the tx of rhabdo

A

Alkalinization of urine to prevent myoglobin deposits in renal tubules.

108
Q

Surgical goal of RESTRICTIVE oPerative bariatric procedures?

A

Reduce and limit the patient’s capacity for intake of food.

109
Q

Restrictive, most common is the creation of

A

Small pouch from the small intestine to the GE junction

110
Q

LAP gastric band advantage

A

Avoidance of permanent alteration gastric anatomy by tissue stapling

111
Q

LAP sleeve Gastrectomy

A

Narrow sleeve created by stapling the stomach vertically.

112
Q

What is excised and removed from the abdomen LAP sleeve gastrectomy.

A

FUNDUS and greater curvature.

113
Q

What is the most effective bariatric procedure to produce safe short and long term weight?

A

RYGB

Roux-en-y Gastric bypass.

114
Q

Weight loss with RYGB is

A

50-60% excess body weight.

115
Q

Resolved in the majority of patients undergoing RYGB

A

DM type II

116
Q

Restrictive surgeries for bariatric are

A

Lap Gastric band

LAP sleeve gastrectomy

117
Q

Largely restrictive surgeries and mildly malabsorptive

A

RYGB

118
Q

Largely malabsorptive, min restrictive surgeries

A

BPD with DS

Biliopancreatic diversion with duodenal switch

119
Q

GFR and RBF with obesity are ____why?

A

INCREASED: because of increased CO and MAP

120
Q

CO and MAP with obesity are

A

INCREASED

121
Q

Renal tubular reabsorption are _______with obesity and why?

A

Increased because of the excessive weight gain.

122
Q

Obesity on natriuresis

A

Impairs natriuresis through sympathetic activation of the RAAS

123
Q

Prolonged obesity results in what with nephron?

A

Loss of nephron function further impairing natriuresis, thus increasing Arterial BP

124
Q

Both obese males and females have increased risk of

A

Renal Cancers

125
Q

Obese males are at increased risk of

A

Prostate CA

126
Q

Obese female are at increased risk of

A

Endometrial and cervical CAs

127
Q

Linear relationship between

A

arthritis and patient weight.

128
Q

Bone with the obese patients?

A

Bone resorption occurs due to limited mobility lead to reduce bone density and contribute to stress fractures.

129
Q

Renal tubular reabsorption are _______with obesity and why?

A

Increased because of the excessive weight gain.

130
Q

Metabolic syndrome is a constellation of _____abnormalities including : DHOG

A

Obesity
Glucose intolerance
HTN
Dyslipidemia

131
Q

Prolonged obesity results in what with nephron?

A

Loss of nephron function further impairing natriuresis, thus increasing Arterial BP

132
Q

Both obese males and females have increased risk of

A

Renal Cancers

133
Q

Endocrine CA : Obese females are at increased risk of

A

Breast CA

134
Q

Obese female are at increased risk of

A

Endometrial and cervical CAs

135
Q

Liver enzymes MOST FREQUENLY elevated in obese patients?

A

Increased ALT AKA
(SGPT, ALAT)
alanine aminotransferase (ALAT)
SGPT serum glutamic-pyruvic transaminase

136
Q

Bone with the obese patients?

A

Bone resorption occurs due to limited mobility lead to reduce bone density and contribute to stress fractures.

137
Q

Gallstones obese vs normal patients

A

30% more chance of occurring in the obese.

138
Q

Metabolic syndrome is a constellation of _____abnormalities including

A

Obesity
Glucose intolerance
HTN
Dyslipidemia

139
Q

Diagnosis of metabolic syndrome requires ____ of how many features?

A

3 out of 5
Central *(android) obesity: WAIST >102cm M; >88cm F
Triglycerides > 150 mg/dL
Reduce HDL < or equal 40 M; < or equal 50 F
HTN : >130/85 or taking antihypertensives
Fasting glucose: > or equal 100 mg/dL

140
Q

Increase linear with BMI

A

Risk of Type II DM

141
Q

Obese females are at increased risk of

A

Breast CA

142
Q

Endocrine CA associated with obese men

A

Thyroid gland adenocarcinoma

143
Q

GI cancer common in obese female patients

A

Gallbladder CA

144
Q

Gastric volume and acidity in the obese patients

A

INCREASED

145
Q

Fasting gastric volume and acid in the OBESE patients? What are they at risk for?

A

obese patients have a gastric volume of >0.35 ml/krg and pH < 2.5
Aspiration and regurgitation.

146
Q

Gastric emptying in the obese

A

Delayed because of INCREASED ABDOMINAL MASS

147
Q

BP and OBESITY

A

SYSTEMIC HTN causes CONCENTRIC (pressure ) HYPERTROPHY Of the LV in normal weight people but CAUSES ECCENTRIC HYPERTROPHY in OBESE PATIENTS

148
Q

Hypertrophy seen with obese patients is

A

ECCENTRIC HYPERTROPHY of LV in OBESE PATIENTS (normal people is CONCENTRIC) 2 Es in eccentric 2 Es in obese

149
Q

Adipose tissue in the OBESITY :

A

Adipose tissue releases a number of bioactive mediators (Cytokines, chemokines , hormones) THAT PROMOTE A CHRONIC SUBCLINICAL INFLAMMATORY STATE.

150
Q

What contribue to the CV , insulin resistance and coagulopathies seen with obesity?

A

Bioactive mediators and inflammatory state

151
Q

Risk of DVT in obese

A

2x greater risk

152
Q

Factor elevated in obese

A

HIGH FACTOR VIII (hemophillia a) associated with increased mortality.

153
Q

Hypertrophy seen with obese patients is

A

CAUSES ECCENTRIC HYPERTROPHY in OBESE PATIENTS

154
Q

ECG changes associated with obesity ?

A

LOW QRS voltage
LV hypertrophy
LA Enlargement
Leftward shift of P wave , QRS complex, T wave axis.

155
Q

ECG changes associated with obesity ? QT

A

Prolonged

156
Q

ECG changes associated with obesity ? T wave

A

flat t waves

157
Q

According to the LAW of laplace , LV hypertrophy

A

LV hypertrophy occurs in an attempt to reduce wall stress

158
Q

Increased LV wall stress leads to :

Compliance of LV, diastolic filling, Pressure, pulmonary system, dysfunction and failure.

A
Hypertrophy
reduced LV compliance
Impaired Diastolic filling 
LV pressures
Pulmonary edema
systolic dysfunction
Biventricular failure.
159
Q

ECG changes associated with obesity ? P wave

A

Leftward shift of P wave , QRS complex, T wave axis.

160
Q

Obesity QRS Voltage

A

Low QRS voltage.

161
Q

BMI normal

A

18.5 - 24.9

162
Q

BMI Overweight

A

25 - 29.9

163
Q

BMI Obesity Class I, II, III

A
30-34.9 Obesity Class I
35-39.9 Obesity Class II
40-49.99 Morbid Obesity Class III
> 50 Superobese
>60 Super superobese
164
Q

What is the definite of android obesity?

A

Apple shape, also known as central obesity

165
Q

Measurement use to diagnosed android obesity? How is android obesity defined for women and men?

A

Waist/hip ratio used. Women is WAIST/HIP ratio greater than 0.85 in men and greater than in women 0.92

166
Q

Waist circumference greater than ____For men denotes an increase risk for Ischemic HD, DM, HTN, HLD, and death

A

40 inch

167
Q

Waist circumference greater than ____For women denotes an increase risk for Ischemic HD, DM, HTN, HLD, and death

A

35 inch

168
Q

What is gynecoid obesity?

A

Primarily found in women, act as energy depots for pregnancy and lactation .

169
Q

Increased waist circumference > 35 inch for women and > 40 for men put them at risk for 5 major consequences

A
Ischemic HD
DM
HTN
HLD
Death
170
Q

Gynecoid vs android which is LESS associated with cardiovascular diseases?

A

Gynecoid fat is less metabolically active

171
Q

What pulmonary disease pattern exhibited by Morbidly obese patients?

A

Restrictive

172
Q

Overtime, wHat happens to chest wall compliance and lung compliance and FRC for the obese patient

A

They develop THORACIC KYPHOSIS and LUMBAR LORDOSIS leading to impaired rib movement and fixation of thorax in an INSPIRATORY POSITION

173
Q

Pulmonary compliance in the obese person is increase or reduced?

A

Reduced by 35% of predicted values.

174
Q

Decreased pulmonary compliance seen with obesity leads to

A

Decline in FRC to less than CC

175
Q

FRC and closing capacity in the obese patients?

A

FRC decrease to LESS than Closing capacity.

176
Q

In the upright position, the obese patients FRC is _____and CC is ____

A

decreased, INCREASE

177
Q

What is the definitive diagnosis of OSA

A

Polysomnography

178
Q

How is the result of a polysomnography interpreted?

A

Apnea/hypopnea index
5-15 events/hr MILD
15-30 events/hr MODERATE
> 30 events/hr SEVERE

179
Q

Physiologic abnormalities with OSA

A

Hypoxemia
Hypercapnia
Pulmonary vasoconstriction
Systemic vasoconstriction

180
Q

Long term OSA lead to

A

Obesity hypoventilation syndrome

181
Q

Obesity hypoventilation syndrome also known as

A

Pickwickian syndrome

182
Q

Presence of both OBESITY and AWAKE arterial hypercapnia PaCo2> 45 in the absence of known causes of hypoventilation supports what diagnosis

A

Obesity hypoventilation syndrome

183
Q

What causes the prolonged responses of some medications given to a patient with morbid obesity?

A

Increased volume o f distribution for lipid soluble drugs

184
Q

Propofol dosing for obese patients (LITM)

A

Induction dose based on LBW

Maintenance dose based on TBW

185
Q

Succinylcholine dosing for obese patients : Intubating dose should be based on what weight and why? 2 reasons?

A

Total body weight:
Because they have increased fluid compartment and pseudocholinesterase levels require HIGHER doses to ensure adequate paralysis

186
Q

All doses based on IBW for obese patients with those three drugs

A

Rocuronium
Vecuronium
Cisatracurium

187
Q

Remifentanil infusion for obese patients are based on

A

Ideal body weight (IBW) because of increased volume of distribution and elimination rates NORMAL

188
Q

Fentanyl and sufentanil loading and maintenance doses in obese patients

A

Loading dose on TBW

Maintenance dose on LBW

189
Q

Sugammadex reversal for obese patients, dosing based on LBW, TBW, IBW?

A

Total Body weight

190
Q

Elimination of fentanyl and sufentanil in the obese patients? You should know that they hav

A

Increase volume of distribution and elimination time correlate with degree of obesity.

191
Q

“Tumescent”

A

means distended, especially by fluids or gas, and comes from the same Latin root as “tumor:· During tumescent liposuction , a combi- nation of JV fluid, dilute lidocaine O.O5% to O. l %, and dilute epinephrine l:l,000,000 (collectively called the wetting solution) is used to emulsifyfat, provide anesthesia, and create hemostasis during liposuction

192
Q

Pharmacokinetics change associated with obesity : CO, BV, LBW, plasma protein binding

A

Increase CO
Increase BV
Increase lean body weight

193
Q

Pharmacokinetics change associated with obesity : Plasma protein binding

A

Changes

194
Q

Total body water with obesity

A

Reduced

195
Q

Pharmacokinetics change associated with obesity : Renal clearance

A

Increased

196
Q

Pharmacokinetics change associated with obesity : Liver

A

Abnormal liver function